Composition



Patented June 30, 1936 wai Charles Sterling Webber, Springfield, and Elbert A. Wilson, Longmeadow, Mass, assignors to The Fiberloid Corporation, Indian Orchard, Mass., a corporation of Massachusetts No Drawing. Application February 6, 1934, Serial No. 709,988

(o1. roe-4o) 1 Claim.

This invention relates to improvements in com' positions of matter and .is'dire'cted more particu arly'to-the provision of compositions of matter in which certain cellulose derivatives are combined with a compatible plasticizer containing certain esters of phthalicacid, with or without other substances such as .addition agents, to provideimproved compositions which are desirable for use in the plastic and analogous arts.- The compositions of this invention are particularly advantageous for use in the manufacture of sheets, rods, tubes, molding compounds, wrapping tissues, laminated glass, artificial silk and leather, varnishes or lacquers, paper coatings and the like.

The principal object of this invention is the provision of cellulose derivative compositions which are permanently tough, transparent and clear and which are stable under the exposure of actinic rays. The compositions of this invention are especially suitable for lamination with one or more sheets of glass so that any scattering of glass particles which might be caused by subjecting the composite to a sudden shock is minimized.

Another object of this invention is the provision of a plastic composition that has enhanced strength at freezing and sub-freezing temperatures such that a glass composite containing the composition will not scatter at any temperature encountered in winter weather.

It is a further object of this invention to provide a cellulose derivative composition which is capable of being readily molded at relatively low temperatures and pressures so that it may be easily laminated with an article of glass. That is to say, the plastic composition of this invention has the capacity to readily flow to conform to the contour of the glass even though the latter may be as irregular as common drawn sheet glass, so that as a result strains that would otherwise be set up in the composite upon cooling are eliminated.

Still another object of this invention is the provision of a composition of matter which may be flowed under pressure onto the surface of a cloth, screen, or the like, and even into the interstices of a cloth, screen, or the like, to form a continuous sheet suitable for artificial leather and the like. Various and other objects of the invention will readily appear to those skilled in the art to which it pertains as the composition is disclosed.

According to this invention, cellulose organic esters such as cellulose acetate or cellulose nitectic mixture.

trate are combined or mixed with acompatible plasticizer, with or withouta common solvent for both, and with or without other useful additional agents. l i 1 Cellulose derivatives have long been used in the plastic arts and it has also been recognized V PATENT orr cs that for satisfactory results-it is 'necessary 'to mix with the cellulose someplasticizing or conditioning agent, such as alpha-chlornaphthalene, ethyl toluene sulphonamide, triphenyl phosphate and the like, for their plastic-inducing properties: in an otherwise brittle basematerial'. r

However, it is a factthat most'of' these pIastlis bound to shatter. This, of course, is a decided disadvantage if the plastic is to be used in a composite with glass, particularly if the composite is to be employed in motor vehicles and the like. In winter weather, at low and freezing temperatures, the value of the prior art cellulose-glass composite, commonly known as non,- shatterable glass, tends to be dissipated.

In providing the composition of this invention two or more plastic-inducing substances are addedto a cellulose organic ester, such as cellulose acetate, in such proportions that the congealing point of the combined plasticizers is appreciably lower than that of either of the plasticizers alone. use a mixture of two or more plasticizers which has the lowest freezing point possible, that is, a eutectic mixture.

We have found that esters of phthalic acid are most suitable for this purpose. That is to say, eutectic mixtures of two or more phthalic acid esters not only are capable of serving well their plastic-inducing function at ordinary temperatures but they have a low congealing point so that the mixture will readily flow at relatively low temperatures.

In one preferred form of the invention, there is added to the cellulose derivative, such as cellulose acetate, a mixture of from approximately 35 to 60 parts by weight of dimethyl phthalate and from approximately 60 to 35 parts by weight of dlethyl phthalate, between which lies the eu- This mixture has been found to be particularly satisfactory since the freezing point-composition curve for mixtures of diethyl phthalate and dimethyl phthalate shows the It is most desirable, of course, to

, tion. A mixtureordimethyiphthalateiwith ethyl" ester of 1 methyl carboxy methyl phthaiate betaacetyl oxyethy-l ,betaihydroxyethyl'phthalate depression of the freezing 'guished' from --a plastic composition containing but one of theabove two plasticizing agents, that is either dimethyl phthalate or diethyl phthalate.

Of course, eutectic mixtures of other estersflaf phthalic acid may be formed, such as dimjeth'yl" phthalate-dimethoxy ethyl phthalate mpmme from'40. to 60 parts of "dknethylyphthalale an df from 60 to 40 parts of dimethoxy ethyl; phthalate: 7

,Also, mixtures of dlmethyl phthalatewith di- "propyl phthalate, dibutyl' phthala ajndiethoxye' ethyl phthalate, methyl methoxy ethyl phthalate," 'or methyl ethoxy' ethyl phthalate' wquld seryet satisfactorily in'the composition of this 'inven-f'" would likewise form eutectic compositionswhich would. function in a celimosederiyative. plastic in a;.-likemanner. c v y V 1 any-event; t -Ithe; preferrai; form ofxthe myention; it is. desirablethat. from 75 :to 100: parts vby; weight of a mixed plasticizer con-o I sist-ing of two or 'moreesters 'ofrphthalic'acidlbe organic ester; The-i freezln-gor -congealing point of eachcomponent ofisuch mixtures issubstan- V g V diethylphthalate anddimethylphthalate. added to approximately 100 parts one, cellulose r 2,046,281 V v V tially lowered so that; as a'result, a stronger;

and therefore more desirable, plastic is produced. Thus it is possible to safely use cellulosic compositions in laminated glasscomposites at freezing Howevenit is desired topointoout that any one 7 o of: the above mixed lasti ize s will serve their .novel function providedtherelative proportions of the respective components are such that gthe freezing point of the mixture is within what may be ealled a1 eutectic range"; Thatois to say, 7 I it is not desired to be limited to only those 'speeificepmport lonsof these esters of'phthalic acidlWhich have the freezing point of the euor sub-freezing temperatures.

tectic mixture, since, mixtures thereof which have s lts'h i 7 While we have described our invention'ln great detail amtwith respect there- OEAWQJjdG not flesire tofbe limited to such-detail and preferredforms," since nmnydianges may freezing within, say, ten degrees of the r point. ofathe eutectic mixture havebeen 'folmdito satisfactorily produce the desired '18- made without departhig fmm thespirit andsoope of invention. 'we 'desire to: claim secure by- Letters Patent s: the United States ist' f As a new. articieofkmauutactureaa plastic composition. for use: in laminated safet-y' I glass com prising "acetate and), eutectic mixture of:

Y ELBERT 'A. wrnsoN.

mama. 

